Add the ability to implement WhiCapsl.

[bigfarts]

Two changes:

1. As discussed, add missing hit_flags to Card::Properties to allow hit_flags to be passed between chips. No chips support this so there will need to be some kind of migration of existing chips to do this (but a lot of them are hardcoding other things too, so they'll need revisions either way).
2. Allow Flinch + Stun. In bnEntity.cpp there's an explicit check that specifically disallows this, but I don't know what the implications of it are. Let me know if I'm way off the mark in taking this out.